--- /dev/null
+/*
+ * ppp_deflate.c - interface the zlib procedures for Deflate compression
+ * and decompression (as used by gzip) to the PPP code.
+ *
+ * Copyright 1994-1998 Paul Mackerras.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+#include <linux/string.h>
+
+#include <linux/ppp_defs.h>
+#include <linux/ppp-comp.h>
+
+#include <linux/zlib.h>
+#include <asm/unaligned.h>
+
+/*
+ * State for a Deflate (de)compressor.
+ */
+struct ppp_deflate_state {
+ int seqno;
+ int w_size;
+ int unit;
+ int mru;
+ int debug;
+ z_stream strm;
+ struct compstat stats;
+};
+
+#define DEFLATE_OVHD 2 /* Deflate overhead/packet */
+
+static void *z_comp_alloc(unsigned char *options, int opt_len);
+static void *z_decomp_alloc(unsigned char *options, int opt_len);
+static void z_comp_free(void *state);
+static void z_decomp_free(void *state);
+static int z_comp_init(void *state, unsigned char *options,
+ int opt_len,
+ int unit, int hdrlen, int debug);
+static int z_decomp_init(void *state, unsigned char *options,
+ int opt_len,
+ int unit, int hdrlen, int mru, int debug);
+static int z_compress(void *state, unsigned char *rptr,
+ unsigned char *obuf,
+ int isize, int osize);
+static void z_incomp(void *state, unsigned char *ibuf, int icnt);
+static int z_decompress(void *state, unsigned char *ibuf,
+ int isize, unsigned char *obuf, int osize);
+static void z_comp_reset(void *state);
+static void z_decomp_reset(void *state);
+static void z_comp_stats(void *state, struct compstat *stats);
+
+/**
+ * z_comp_free - free the memory used by a compressor
+ * @arg: pointer to the private state for the compressor.
+ */
+static void z_comp_free(void *arg)
+{
+ struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+
+ if (state) {
+ zlib_deflateEnd(&state->strm);
+ vfree(state->strm.workspace);
+ kfree(state);
+ }
+}
+
+/**
+ * z_comp_alloc - allocate space for a compressor.
+ * @options: pointer to CCP option data
+ * @opt_len: length of the CCP option at @options.
+ *
+ * The @options pointer points to the a buffer containing the
+ * CCP option data for the compression being negotiated. It is
+ * formatted according to RFC1979, and describes the window
+ * size that the peer is requesting that we use in compressing
+ * data to be sent to it.
+ *
+ * Returns the pointer to the private state for the compressor,
+ * or NULL if we could not allocate enough memory.
+ */
+static void *z_comp_alloc(unsigned char *options, int opt_len)
+{
+ struct ppp_deflate_state *state;
+ int w_size;
+
+ if (opt_len != CILEN_DEFLATE ||
+ (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
+ options[1] != CILEN_DEFLATE ||
+ DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
+ options[3] != DEFLATE_CHK_SEQUENCE)
+ return NULL;
+ w_size = DEFLATE_SIZE(options[2]);
+ if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
+ return NULL;
+
+ state = kzalloc(sizeof(*state),
+ GFP_KERNEL);
+ if (state == NULL)
+ return NULL;
+
+ state->strm.next_in = NULL;
+ state->w_size = w_size;
+ state->strm.workspace = vmalloc(zlib_deflate_workspacesize(-w_size, 8));
+ if (state->strm.workspace == NULL)
+ goto out_free;
+
+ if (zlib_deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION,
+ DEFLATE_METHOD_VAL, -w_size, 8, Z_DEFAULT_STRATEGY)
+ != Z_OK)
+ goto out_free;
+ return (void *) state;
+
+out_free:
+ z_comp_free(state);
+ return NULL;
+}
+
+/**
+ * z_comp_init - initialize a previously-allocated compressor.
+ * @arg: pointer to the private state for the compressor
+ * @options: pointer to the CCP option data describing the
+ * compression that was negotiated with the peer
+ * @opt_len: length of the CCP option data at @options
+ * @unit: PPP unit number for diagnostic messages
+ * @hdrlen: ignored (present for backwards compatibility)
+ * @debug: debug flag; if non-zero, debug messages are printed.
+ *
+ * The CCP options described by @options must match the options
+ * specified when the compressor was allocated. The compressor
+ * history is reset. Returns 0 for failure (CCP options don't
+ * match) or 1 for success.
+ */
+static int z_comp_init(void *arg, unsigned char *options, int opt_len,
+ int unit, int hdrlen, int debug)
+{
+ struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+
+ if (opt_len < CILEN_DEFLATE ||
+ (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
+ options[1] != CILEN_DEFLATE ||
+ DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
+ DEFLATE_SIZE(options[2]) != state->w_size ||
+ options[3] != DEFLATE_CHK_SEQUENCE)
+ return 0;
+
+ state->seqno = 0;
+ state->unit = unit;
+ state->debug = debug;
+
+ zlib_deflateReset(&state->strm);
+
+ return 1;
+}
+
+/**
+ * z_comp_reset - reset a previously-allocated compressor.
+ * @arg: pointer to private state for the compressor.
+ *
+ * This clears the history for the compressor and makes it
+ * ready to start emitting a new compressed stream.
+ */
+static void z_comp_reset(void *arg)
+{
+ struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+
+ state->seqno = 0;
+ zlib_deflateReset(&state->strm);
+}
+
+/**
+ * z_compress - compress a PPP packet with Deflate compression.
+ * @arg: pointer to private state for the compressor
+ * @rptr: uncompressed packet (input)
+ * @obuf: compressed packet (output)
+ * @isize: size of uncompressed packet
+ * @osize: space available at @obuf
+ *
+ * Returns the length of the compressed packet, or 0 if the
+ * packet is incompressible.
+ */
+static int z_compress(void *arg, unsigned char *rptr, unsigned char *obuf,
+ int isize, int osize)
+{
+ struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+ int r, proto, off, olen, oavail;
+ unsigned char *wptr;
+
+ /*
+ * Check that the protocol is in the range we handle.
+ */
+ proto = PPP_PROTOCOL(rptr);
+ if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
+ return 0;
+
+ /* Don't generate compressed packets which are larger than
+ the uncompressed packet. */
+ if (osize > isize)
+ osize = isize;
+
+ wptr = obuf;
+
+ /*
+ * Copy over the PPP header and store the 2-byte sequence number.
+ */
+ wptr[0] = PPP_ADDRESS(rptr);
+ wptr[1] = PPP_CONTROL(rptr);
+ put_unaligned_be16(PPP_COMP, wptr + 2);
+ wptr += PPP_HDRLEN;
+ put_unaligned_be16(state->seqno, wptr);
+ wptr += DEFLATE_OVHD;
+ olen = PPP_HDRLEN + DEFLATE_OVHD;
+ state->strm.next_out = wptr;
+ state->strm.avail_out = oavail = osize - olen;
+ ++state->seqno;
+
+ off = (proto > 0xff) ? 2 : 3; /* skip 1st proto byte if 0 */
+ rptr += off;
+ state->strm.next_in = rptr;
+ state->strm.avail_in = (isize - off);
+
+ for (;;) {
+ r = zlib_deflate(&state->strm, Z_PACKET_FLUSH);
+ if (r != Z_OK) {
+ if (state->debug)
+ printk(KERN_ERR
+ "z_compress: deflate returned %d\n", r);
+ break;
+ }
+ if (state->strm.avail_out == 0) {
+ olen += oavail;
+ state->strm.next_out = NULL;
+ state->strm.avail_out = oavail = 1000000;
+ } else {
+ break; /* all done */
+ }
+ }
+ olen += oavail - state->strm.avail_out;
+
+ /*
+ * See if we managed to reduce the size of the packet.
+ */
+ if (olen < isize && olen <= osize) {
+ state->stats.comp_bytes += olen;
+ state->stats.comp_packets++;
+ } else {
+ state->stats.inc_bytes += isize;
+ state->stats.inc_packets++;
+ olen = 0;
+ }
+ state->stats.unc_bytes += isize;
+ state->stats.unc_packets++;
+
+ return olen;
+}
+
+/**
+ * z_comp_stats - return compression statistics for a compressor
+ * or decompressor.
+ * @arg: pointer to private space for the (de)compressor
+ * @stats: pointer to a struct compstat to receive the result.
+ */
+static void z_comp_stats(void *arg, struct compstat *stats)
+{
+ struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+
+ *stats = state->stats;
+}
+
+/**
+ * z_decomp_free - Free the memory used by a decompressor.
+ * @arg: pointer to private space for the decompressor.
+ */
+static void z_decomp_free(void *arg)
+{
+ struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+
+ if (state) {
+ zlib_inflateEnd(&state->strm);
+ vfree(state->strm.workspace);
+ kfree(state);
+ }
+}
+
+/**
+ * z_decomp_alloc - allocate space for a decompressor.
+ * @options: pointer to CCP option data
+ * @opt_len: length of the CCP option at @options.
+ *
+ * The @options pointer points to the a buffer containing the
+ * CCP option data for the compression being negotiated. It is
+ * formatted according to RFC1979, and describes the window
+ * size that we are requesting the peer to use in compressing
+ * data to be sent to us.
+ *
+ * Returns the pointer to the private state for the decompressor,
+ * or NULL if we could not allocate enough memory.
+ */
+static void *z_decomp_alloc(unsigned char *options, int opt_len)
+{
+ struct ppp_deflate_state *state;
+ int w_size;
+
+ if (opt_len != CILEN_DEFLATE ||
+ (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
+ options[1] != CILEN_DEFLATE ||
+ DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
+ options[3] != DEFLATE_CHK_SEQUENCE)
+ return NULL;
+ w_size = DEFLATE_SIZE(options[2]);
+ if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
+ return NULL;
+
+ state = kzalloc(sizeof(*state), GFP_KERNEL);
+ if (state == NULL)
+ return NULL;
+
+ state->w_size = w_size;
+ state->strm.next_out = NULL;
+ state->strm.workspace = vmalloc(zlib_inflate_workspacesize());
+ if (state->strm.workspace == NULL)
+ goto out_free;
+
+ if (zlib_inflateInit2(&state->strm, -w_size) != Z_OK)
+ goto out_free;
+ return (void *) state;
+
+out_free:
+ z_decomp_free(state);
+ return NULL;
+}
+
+/**
+ * z_decomp_init - initialize a previously-allocated decompressor.
+ * @arg: pointer to the private state for the decompressor
+ * @options: pointer to the CCP option data describing the
+ * compression that was negotiated with the peer
+ * @opt_len: length of the CCP option data at @options
+ * @unit: PPP unit number for diagnostic messages
+ * @hdrlen: ignored (present for backwards compatibility)
+ * @mru: maximum length of decompressed packets
+ * @debug: debug flag; if non-zero, debug messages are printed.
+ *
+ * The CCP options described by @options must match the options
+ * specified when the decompressor was allocated. The decompressor
+ * history is reset. Returns 0 for failure (CCP options don't
+ * match) or 1 for success.
+ */
+static int z_decomp_init(void *arg, unsigned char *options, int opt_len,
+ int unit, int hdrlen, int mru, int debug)
+{
+ struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+
+ if (opt_len < CILEN_DEFLATE ||
+ (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT) ||
+ options[1] != CILEN_DEFLATE ||
+ DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL ||
+ DEFLATE_SIZE(options[2]) != state->w_size ||
+ options[3] != DEFLATE_CHK_SEQUENCE)
+ return 0;
+
+ state->seqno = 0;
+ state->unit = unit;
+ state->debug = debug;
+ state->mru = mru;
+
+ zlib_inflateReset(&state->strm);
+
+ return 1;
+}
+
+/**
+ * z_decomp_reset - reset a previously-allocated decompressor.
+ * @arg: pointer to private state for the decompressor.
+ *
+ * This clears the history for the decompressor and makes it
+ * ready to receive a new compressed stream.
+ */
+static void z_decomp_reset(void *arg)
+{
+ struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+
+ state->seqno = 0;
+ zlib_inflateReset(&state->strm);
+}
+
+/**
+ * z_decompress - decompress a Deflate-compressed packet.
+ * @arg: pointer to private state for the decompressor
+ * @ibuf: pointer to input (compressed) packet data
+ * @isize: length of input packet
+ * @obuf: pointer to space for output (decompressed) packet
+ * @osize: amount of space available at @obuf
+ *
+ * Because of patent problems, we return DECOMP_ERROR for errors
+ * found by inspecting the input data and for system problems, but
+ * DECOMP_FATALERROR for any errors which could possibly be said to
+ * be being detected "after" decompression. For DECOMP_ERROR,
+ * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
+ * infringing a patent of Motorola's if we do, so we take CCP down
+ * instead.
+ *
+ * Given that the frame has the correct sequence number and a good FCS,
+ * errors such as invalid codes in the input most likely indicate a
+ * bug, so we return DECOMP_FATALERROR for them in order to turn off
+ * compression, even though they are detected by inspecting the input.
+ */
+static int z_decompress(void *arg, unsigned char *ibuf, int isize,
+ unsigned char *obuf, int osize)
+{
+ struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+ int olen, seq, r;
+ int decode_proto, overflow;
+ unsigned char overflow_buf[1];
+
+ if (isize <= PPP_HDRLEN + DEFLATE_OVHD) {
+ if (state->debug)
+ printk(KERN_DEBUG "z_decompress%d: short pkt (%d)\n",
+ state->unit, isize);
+ return DECOMP_ERROR;
+ }
+
+ /* Check the sequence number. */
+ seq = get_unaligned_be16(ibuf + PPP_HDRLEN);
+ if (seq != (state->seqno & 0xffff)) {
+ if (state->debug)
+ printk(KERN_DEBUG "z_decompress%d: bad seq # %d, expected %d\n",
+ state->unit, seq, state->seqno & 0xffff);
+ return DECOMP_ERROR;
+ }
+ ++state->seqno;
+
+ /*
+ * Fill in the first part of the PPP header. The protocol field
+ * comes from the decompressed data.
+ */
+ obuf[0] = PPP_ADDRESS(ibuf);
+ obuf[1] = PPP_CONTROL(ibuf);
+ obuf[2] = 0;
+
+ /*
+ * Set up to call inflate. We set avail_out to 1 initially so we can
+ * look at the first byte of the output and decide whether we have
+ * a 1-byte or 2-byte protocol field.
+ */
+ state->strm.next_in = ibuf + PPP_HDRLEN + DEFLATE_OVHD;
+ state->strm.avail_in = isize - (PPP_HDRLEN + DEFLATE_OVHD);
+ state->strm.next_out = obuf + 3;
+ state->strm.avail_out = 1;
+ decode_proto = 1;
+ overflow = 0;
+
+ /*
+ * Call inflate, supplying more input or output as needed.
+ */
+ for (;;) {
+ r = zlib_inflate(&state->strm, Z_PACKET_FLUSH);
+ if (r != Z_OK) {
+ if (state->debug)
+ printk(KERN_DEBUG "z_decompress%d: inflate returned %d (%s)\n",
+ state->unit, r, (state->strm.msg? state->strm.msg: ""));
+ return DECOMP_FATALERROR;
+ }
+ if (state->strm.avail_out != 0)
+ break; /* all done */
+ if (decode_proto) {
+ state->strm.avail_out = osize - PPP_HDRLEN;
+ if ((obuf[3] & 1) == 0) {
+ /* 2-byte protocol field */
+ obuf[2] = obuf[3];
+ --state->strm.next_out;
+ ++state->strm.avail_out;
+ }
+ decode_proto = 0;
+ } else if (!overflow) {
+ /*
+ * We've filled up the output buffer; the only way to
+ * find out whether inflate has any more characters
+ * left is to give it another byte of output space.
+ */
+ state->strm.next_out = overflow_buf;
+ state->strm.avail_out = 1;
+ overflow = 1;
+ } else {
+ if (state->debug)
+ printk(KERN_DEBUG "z_decompress%d: ran out of mru\n",
+ state->unit);
+ return DECOMP_FATALERROR;
+ }
+ }
+
+ if (decode_proto) {
+ if (state->debug)
+ printk(KERN_DEBUG "z_decompress%d: didn't get proto\n",
+ state->unit);
+ return DECOMP_ERROR;
+ }
+
+ olen = osize + overflow - state->strm.avail_out;
+ state->stats.unc_bytes += olen;
+ state->stats.unc_packets++;
+ state->stats.comp_bytes += isize;
+ state->stats.comp_packets++;
+
+ return olen;
+}
+
+/**
+ * z_incomp - add incompressible input data to the history.
+ * @arg: pointer to private state for the decompressor
+ * @ibuf: pointer to input packet data
+ * @icnt: length of input data.
+ */
+static void z_incomp(void *arg, unsigned char *ibuf, int icnt)
+{
+ struct ppp_deflate_state *state = (struct ppp_deflate_state *) arg;
+ int proto, r;
+
+ /*
+ * Check that the protocol is one we handle.
+ */
+ proto = PPP_PROTOCOL(ibuf);
+ if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
+ return;
+
+ ++state->seqno;
+
+ /*
+ * We start at the either the 1st or 2nd byte of the protocol field,
+ * depending on whether the protocol value is compressible.
+ */
+ state->strm.next_in = ibuf + 3;
+ state->strm.avail_in = icnt - 3;
+ if (proto > 0xff) {
+ --state->strm.next_in;
+ ++state->strm.avail_in;
+ }
+
+ r = zlib_inflateIncomp(&state->strm);
+ if (r != Z_OK) {
+ /* gak! */
+ if (state->debug) {
+ printk(KERN_DEBUG "z_incomp%d: inflateIncomp returned %d (%s)\n",
+ state->unit, r, (state->strm.msg? state->strm.msg: ""));
+ }
+ return;
+ }
+
+ /*
+ * Update stats.
+ */
+ state->stats.inc_bytes += icnt;
+ state->stats.inc_packets++;
+ state->stats.unc_bytes += icnt;
+ state->stats.unc_packets++;
+}
+
+/*************************************************************
+ * Module interface table
+ *************************************************************/
+
+/* These are in ppp_generic.c */
+extern int ppp_register_compressor (struct compressor *cp);
+extern void ppp_unregister_compressor (struct compressor *cp);
+
+/*
+ * Procedures exported to if_ppp.c.
+ */
+static struct compressor ppp_deflate = {
+ .compress_proto = CI_DEFLATE,
+ .comp_alloc = z_comp_alloc,
+ .comp_free = z_comp_free,
+ .comp_init = z_comp_init,
+ .comp_reset = z_comp_reset,
+ .compress = z_compress,
+ .comp_stat = z_comp_stats,
+ .decomp_alloc = z_decomp_alloc,
+ .decomp_free = z_decomp_free,
+ .decomp_init = z_decomp_init,
+ .decomp_reset = z_decomp_reset,
+ .decompress = z_decompress,
+ .incomp = z_incomp,
+ .decomp_stat = z_comp_stats,
+ .owner = THIS_MODULE
+};
+
+static struct compressor ppp_deflate_draft = {
+ .compress_proto = CI_DEFLATE_DRAFT,
+ .comp_alloc = z_comp_alloc,
+ .comp_free = z_comp_free,
+ .comp_init = z_comp_init,
+ .comp_reset = z_comp_reset,
+ .compress = z_compress,
+ .comp_stat = z_comp_stats,
+ .decomp_alloc = z_decomp_alloc,
+ .decomp_free = z_decomp_free,
+ .decomp_init = z_decomp_init,
+ .decomp_reset = z_decomp_reset,
+ .decompress = z_decompress,
+ .incomp = z_incomp,
+ .decomp_stat = z_comp_stats,
+ .owner = THIS_MODULE
+};
+
+static int __init deflate_init(void)
+{
+ int answer = ppp_register_compressor(&ppp_deflate);
+ if (answer == 0)
+ printk(KERN_INFO
+ "PPP Deflate Compression module registered\n");
+ ppp_register_compressor(&ppp_deflate_draft);
+ return answer;
+}
+
+static void __exit deflate_cleanup(void)
+{
+ ppp_unregister_compressor(&ppp_deflate);
+ ppp_unregister_compressor(&ppp_deflate_draft);
+}
+
+module_init(deflate_init);
+module_exit(deflate_cleanup);
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE));
+MODULE_ALIAS("ppp-compress-" __stringify(CI_DEFLATE_DRAFT));
Code Review / kvmfornfv.git / blobdiff